are you running tubes? tubelss? tubular?
i've run the PDX as a clincher with tubes and it was awesome in all conditions.
i ran spesh captn control last season tubeless. also great. solid seal on my easton rims and I never burped.
this season i lucked into some easton carbon tubulars and will be gluing up some MXPs this week. we don't really get super heavy mud here in norcal. it can get wet of course, but nothing super sticky or deep. for the classic chevron/grifo type tread pattern, the MXP has the most aggressive side/shoulder treads by far.
I've run the PDX Tubular for a season alongside Challenge Grifos and Dugast Small Birds and kept coming back to the PDX tires to the point that I'm going to run them for every race this year on my Geared bike and SS rig. As one of my teammates put it, they are pretty much a B+ in every condition and I have run them from 25 to 17 psi depending on the conditions under a 145 lb rider.
I won't deny that Dugast/FMB have better tires but I felt they were really touchy on tire pressure for course conditions and the silk/cotton cases deteriorate quickly compared to the all rubber tubeless tubulars. The PDX's are just super reliable and are the best choice until someone else is paying for your gear.
When I ran clinchers I loved Michelin Mud2's with good success. I currently run MXP clinchers for training and I really like everything Clement I have tried.